Update service_container.rst

[zer0uno]

if a public service should not be fetched by $container->get(), how should it be fetched? The example shows the use of $container->get(), so I think there was a typo and it should be changed from "public" => "private"

[dbrumann]

Private services can not be fetched from the container, public ones can (but should not). I think the point is, that fetching any service from the container is regarded bad practice.

Instead this should probably point to injecting services and service subscribers & locators as recommended alternatives.

[zer0uno]

@dbrumann I understand and I agree you. So at this point I would say that the documentation should be a little bit clearer. It let me confused seeing in the example the use of $container->get() but then reading that it shouldn't be done. IMHO the sentence could be fine-tuned in this way:

From:

As a best practice, you should only create private services, which will happen
automatically. And also, you should not use the $container->get() method to
fetch public services.

To:

As a best practice, you should only create private services, which will happen
automatically. And also, despite the example shows it , you should not use the $container->get() method to fetch public services.

[dbrumann]

How about:

As a best practice, you should only create *private* services.
This allows for safe container optimizations, e.g. removing
unused services. You should not use ``$container->get()``
to fetch public services, as it will make it harder to make those
services private later. Instead consider :ref:`injecting services <_services-constructor-injection>`
or using :doc:`Service Subscribers or Locators </service_container/service_subscribers_locators>`.

I prefer this over the old text, because it not only tells you not to do it, but also why and what alternatives you have. What do you think?

[zer0uno]

Totally agree, really better especially because it tells you why you should do that.

[javiereguiluz]

Thanks @zer0uno! I did the changes proposed by @dbrumann too while merging.